1. Field of the Invention
The present invention relates to a circuit arrangement for correcting the attenuation characteristics of a communication transmission link.
2. Description of the Prior Art
It is often necessary and desirable to compensate and correct the attenuation characteristic of communication transmission links by using adjustable attenuators and wherein a measuring transmitter produces a measuring signal having a constant amplitude and a variable frequency that can be varied over the transmission frequency band which is passed through the communication transmission link and is then fed to an analyzing device by a switch which determines the frequency dependent amplitude fluctuation over the pass band.
A circuit arrangement of this type is disclosed in the publication "Messgeraete fuer die Nachrichtentechnik" July 1975, No. 4 published by Siemens AG of Munich, West Germany. In this arrangement, the measuring signal is scanned over the entire transmission frequency band and the received measuring signal is supplied to a rectifier circuit and is then analyzed such that the variations in the envelope curve which occur during each scanning period can be determined in a second rectifier circuit. The output of this circuit then provides a basis for measuring the distortions present in the communication transmission link and forms the basis for adjusting each individual adjusting element of the attenuation correctors.